Weather in Wargames

In my experience, weather is an important addition to wargames, but it is one of the most likely things to get forgotten about when you are trying to rally the troops one last time at about 2am, and it is certainly one of the most likely things to be dropped from the rules for big games.

Accordingly, I really only consider the weather in detail in computerised games – the old computer, he never forgets, he never gets tired. I’m sitting here this morning, happy that the last lot of snow has gone, but aware from the TV news that more is expected, so some mention of weather seems appropriate.

I have to apologise immediately for the fact that, since they are primarily intended for Summer campaigns in Spain, my weather rules, in their present form, do not cover snow or extreme temperature, neither do they allow for fog/mist (except by implication). Oh – and wind isn’t covered either. In fact, I’m becoming increasingly ashamed of the whole thing as I write.

So this is just an outline – food for thought, if you like. If you find the ideas interesting, I’m confident you can easily improve on what I do, or produce something more suitable for your own games. My weather rules are very much based in the scale and style of games I fight. For example, my main Napoleonic rules have 30-minute bounds and 200-pace hexes, and do not allow for formed musket volley fire – musketry is included in close combat, and the effect of weather on the combat rules reflects this. My MEP Grand Tactical variant will use the same set-up in its automated form, with some adjustment for the 1-hour bounds, the halved ground-scale and the simplified combat rules.

Although the implementation of these rules is on a computer, I shall attempt to illustrate them in the form of dice-throws.

My starting point is a simple, linear, numerical barometer which I think I originally adopted from Charlie Wesencraft (or it might have been Featherstone) about 40 years ago. You can use a cardboard track, or a homemade numbered pegboard – whatever you like. You start with a 2D6 throw to set the weather indicator (wr) – the detail of all this is set out in the attached note – 2 means that it’s fine, 12 that it’s bucketing down with rain.

There are 4 indicators, Weather, Visibility, Mud and Dampness. You’ll need to keep track of the time of day, and determine (at the outset) the official time of dusk, and you’ll need a pair of weather dice – just normal 6-sided dice, but different colours. I use a white one and a black – where necessary, the white counts as +ve and the black as –ve – in all that follows, w is the white dice score, and b the black one. At the end of each bound, roll the 2 weather dice once and adjust the indicators (note this is just a single roll of the 2 dice - eveything can be worked out from this one roll):

Weather (wr), which is the main sliding barometer – this is set initially by rolling the weather dice and adding them together (w + b) – thereafter it is moved up and down each bound – increase by 1 if w > b, decrease by 1 if w < b. If w = b then it stays the same.

Visibility (visi), is the number of hexagons at which units may be seen on the tabletop, and thus the limit of artillery fire. The distance at which Blinds may be spotted, and it which generals may influence the conduct and discipline of their troops is also limited by small values of visi. visi is calculated as (12 – wr), tweaked for the onset of dusk and given a minimum value of 1.

Mud (mud), which is another sliding scale, is initially set equal to b, and its subsequent change is driven by the current value of wr and the value of (w + b) each bound – progressively higher values of mud will limit artillery “bounce-through” for deep targets, prevent the use of movement bonuses, reduce movement rates for all troops, and ultimately prevent all movement of artillery and vehicles.

Dampness (damp) , is initially set to w, and subsequently changes in a manner very similar to mud. damp is a measure of the effect of wet weather on powder-dependent troops. At high values, it stops skirmish fire, reduces the combat effectiveness of infantry and, ultimately, also limits the effects of artillery fire.


At the outset, the start time is set, and the time of dusk (from a scenario, or whatever), and the initial values of wr, visi, mud and damp are set, as described. . If they agree to do so, the generals may request a re-throw, but they may only do this twice – after 2 recalculations they must accept the conditions as given.